i;8 OUR INSECT FRIENDS AND FOES 



flowers, or the sap or gum of trees. Bembex 

 rostrata, however, is an exception to the general 

 rule, although she hollows out a burrow and 

 places an egg and suitable provender within it, 

 she does not then altogether abandon it, as do the 

 majority of her kind. The Bembex makes her 

 burrow in fine, shifting sand, of so light a 

 nature that when she comes out of the narrow 

 tunnel the sand falls in behind her and closes 

 the entrance. A winding, narrow passage, from 

 eight to twelve inches long, leads down to firmer 

 soil, and here a chamber is roughly excavated 

 so that the walls are firm enough not to cave 

 in and bury the worker or the future larva. In 

 this chamber the Bembex places a very meagre 

 ration, consisting of a small fly ; she then lays 

 an egg, and leaves the burrow, which automati- 

 cally closes after her by the falling in of the 

 sand. She then scrapes and smooths the sand 

 over the entrance with the greatest care, so that 

 all trace of the tunnel may be concealed, and 

 flies off, in all probability to construct other 

 chambers and furnish them in the same way. 



In about three days' time Mother Bembex 

 returns, bringing with her a further supply of 

 food in the shape of another fly. Without the 

 slightest hesitation she flies straight to the spot 

 where her nest lies hidden, lightly scrapes the 

 sand with her fore-feet, pushes it away with her 

 head, and dives below to the underground 

 chamber. There she finds that the young larva 

 (which had hatched out from the egg about 

 twenty-four hours previously) has already 

 finished the first meal she had provided for it, 



